Abstract: A purification process for cyclic formals, in which water is efficiently removed from a crude cyclic formal, namely, a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only a very small amount of water.The purification process for cyclic formals is characterized by the steps of supplying a mixture of a cyclic formal and water into a distillation tower, effecting distillation while supplying a hydrophilic solvent (A) having a boiling point from 180.degree. to 250.degree. C. into the distillation tower at a position higher than the supply position of the mixture, and taking out a purified cyclic formal as a distillate.

Abstract: A purification process for cyclic formals, in which water is efficiently removed from a crude cyclic formal, namely, a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only a very small amount of water.The purification process for cyclic formals is characterized by the following two purification steps:(1) Supplying a mixture of a cyclic formal and water into a distillation tower at a supply position, and effecting distillation while supplying a hydrophilic solvent (A) having a boiling point from 180.degree. to 250.degree. C. at a position higher than the supply position of the mixture to take out a cyclic formal (X) containing 100 to 5000 ppm of water as a distillate, and(2) Distilling the cyclic formal (X) obtained in step (1) or treating it with a dehydrant to obtain a purified cyclic formal (Y) which contains less water than in the cyclic formal (X).

Abstract: A purification process for cyclic formals, in which water is efficiently removed from a crude cyclic formal, namely, a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only extremely small amounts of water and impurities.The purification process for cyclic formals is characterized by the steps of supplying a mixture of a cyclic formal and water into a distillation tower, effecting distillation while supplying a hydrophilic solver (A) having a boiling point from 180.degree. to 250.degree. C. and a purified cyclic formal (X) containing not more than 200 ppm of water into the distillation tower at positions higher than the supply position of the mixture and higher than the supply position of the hydrophilic solvent (A), respectively, and taking out a purified cyclic formal from the top of the tower as a distillate.

Abstract: A method of preparing cyclic formals which contain only small amounts of by-product impurities and unreacted starting materials, and which are ready to be purified.In preparing a cyclic formal by reacting alkylene glycol with formaldehyde in the presence of a catalyst, a reaction vessel provided with a vapor-liquid contact zone at the upper part thereof is used. Vapor generated from the reaction mixture and containing a cyclic formal goes up and passes through the vapor-liquid contact zone to be condensed. While part of the condensate is returned to the vapor-liquid contact zone, the remainder of the condensate is taken out as a distillate.

Abstract: A purification process for cyclic formals, in which water is efficiently removed from a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only an extremely small amount of water.The purification process for cyclic formals is characterized by the steps of supplying a mixture of a cyclic formal and water into a distillation tower, effecting distillation while supplying n-pentane into the distillation tower and taking out a purified cyclic formal as a bottom liquid.

Abstract: An improvement for manufacturing paraformaldehyde prills from an aqueous solution of formaldehyde which comprises polymerizing the formaldehyde in the presence of a catalyst of sodium hydroxide in a concentration of from about 0.5 to about 5 ppm, aging the resulting mixture at about 100.degree. to about 130.degree. C. for about 10 to about 60 minutes, spraying the aged mixture into a prilling tower at from about 100.degree. to about 130.degree. C., collecting the prills in a fluidized bed at the base of the tower at from about 45.degree. to about 60.degree. C., removing the prills to a separate vessel where the prills further polymerize and dry at from about 15.degree. to about 30.degree. C. for about 3 to about 5 hours while operating the vessel in a plugged flow manner, and collecting the resulting prills.

Abstract: A process is described for separating soluble copper and manganese catalysts from organic saturated monocarboxylic acids having 3 to 9 carbon atoms by precipitating the copper and manganese as oxalates.

Abstract: The tendency of liquid paraformaldehyde containing water and paraformaldehyde in, for example, approximately 80% to approximately 90% concentration to precipitate solid paraformaldehyde therefrom is retarded by the incorporation thereinto of an effective amount of a moderator or stabilizer selected from the group consisting of polyacrylic acid, tartaric acid, dl-malic acid, ethylenediaminetetraacetic acid, and citric acid. The prior-art stabilizers known and used for lower-concentration formaldehyde solutions of, for example, about 50% strength are not effective. Conversely, the present moderators are not effective in the lower-concentration solutions.

Abstract: An improved process for oxidizing an amine to the corresponding amine oxide with peracetic acid comprises carrying out the reaction in a distillation column, using as oxidant the gaseous mixture of peracetic acid and acetaldehyde resulting from the vapor-phase oxidation of acetaldehyde with oxygen. The amine is introduced in liquid form into the upper portion of the distillation column while the gaseous mixture of peracetic acid and acetaldehyde is simultaneously introduced into an intermediate location in the column. Reaction takes place within the column, with acetic acid and acetaldehyde being withdrawn as vapor from the top while a liquid comprising the amine oxide product is recovered from the base.